Brush type rotary tools and the like



Nov. 1, 1966 v. K. CHARVAT 281,882

BRUSH TYPE ROTARY TOOLS AND THE LIKE Filed Feb. 27, 1964 2 Sheets-Sheet1 INVENTOR. VZ RNM/KT ('HARVA T BY Nov. 1, 1966 v. K. CHARVAT 3,281,882

BRUSH TYPE ROTARY TOOLS AND THE LIKE Filed Feb. 27, 1964 2 Sheets-Sheet2 INVENTOR. Vlmmom KT 611,412 VA T 3,281,882 BRUSH TYPE ROTARY TOOLS ANDTHE LIKE Vernon K. Charvat, Bay Village, ()hio, assignor to The OsbornManufacturing Company, Cleveland, Ohio, a corporation of Ohio Filed Feb.27, 1964, Ser. No. 347,754 6 Claims. (Cl. 15-479) This application is acontinuation-in-part or my prior co-pending application Serial No.834,091, filed August 17, 1959, now Patent No. 3,129,269.

The present invention relates generally to brush type rotary tools, andmore particularly to power driven rotary brushes having plastic intrudedinto the body of brush material to support and regulate the action ofthe latter, 'but the product may also find utility for other purposesincluding use as a supporting or traction wheel for various types ofvehicles.

As shown in Peterson Patent No. 2,826,776 and Stingley Patent 2,950,495,it has heretofore been proposed to make brushing tools of various typesby combining with brush bristle material a body of plastic or resilientelastomeric material, and a number of such plastic materials have beenemployed including natural rubber and various kinds of artificialrubber, and synthetic resins such as polychloroprene which may beafforded a cellular structure by incorporation of suitable gas formingingredients therein. Particularly suitable plastic materials for thepurpose are the polyurethanes, including polyurethane rubber, thesebeing relatively liquid when incorporated while the constituents are yetincompletely reacted. However, in all cases there has remained thedifficult problem of introducing the selected material between the brushbristles so as uniformly to coat the latter and fill the spacestherebetween. The problem is particularly acute where the brush bristleare of relatively fine filamentous form or lack sufi'lcient stiffness sothat they may become easily disarranged and tangled.

One of the principal objects of the present invention is accordingly toprovide brush type rotary tools and like articles wherein centrifugalforce is utilized to distribute the plastic material between the brushbristles while at the same time the latter are effectively maintained indesired position and spaced apart relationship. As a result of employingthis method, a product is obtained of exceptionally uniform and balancedconstruction with a brushing face of uniform density and bristle tipconcentration.

Another object of the invention is initially to distribute the plasticmaterial in a region adjacent the outer working ends of the brushbristles and then to cause such plastic material to foam not only toproduce a cellular structure in the finished article but also to causesuch plastic material to expand inwardly toward the basal ends of thebrush bristles in a direction generally longitudinally of the latter,thereby etfecting thorough and uniform intrusion of the plastic materialwithout any tendency laterally to compact the body of brush bristlematerial.

Still another object is to intrude plastic or other material into thebody of brush material of a power driven rotary wheel type brush whereinsuch intruded material is caused to flow radially inwardly from an outerannular region encompassing the brush face so that such material isintruded substantially longitudinally of the radially disposed bristleor like elements.

A further object is to provide a novel brushing tool in which thebrushing elements such as hard straight wire bristles or soft flexiblecord, for example, extend substantially directly radially in a uniformlyspaced manner with a resin or plastic material, usually foamed,therebetween.

ited States Patent Other objects of the invention will appear as thedescription proceeds.

To the accomplishment of the foregoing and related ends, said inventionthen comprises the features hereinafter fully described and particularlypointed out in the claims, the following description and the annexeddrawing setting forth in detail certain illustrative embodiments of theinvention, these being indicative, however, of but a few of the variousways in which the principle of the invention may be employed.

In said annexed drawing:

FIG. 1 is a semi-diagrammatic axial end view of a brush type rotary toolor wheel made in accordance with my invention;

FIG. 2 is a diametral transverse section of such tool or wheel taken onthe line 22 on FIG. 1;

FIG. 3 is a diagrammatic elevation partly in vertical cross-section of acircular mold mounted upon a turntable or centrifuge adapted for theproduction of a rotary tool or wheel of the type generally illustratedin FIGS. 1 and 2, the brush component of such wheel being shown properlylocated in the mold.

FIGS. 4-9 inclusive are diagrammatic detail views similar to FIG. 3illustrating successive operative stages in the production of the newcomposite brushing tool or wheel;

FIG. 10 is a transverse section similar to FIG. 9 but showing the toolas formed with a non-foaming plastic composition; and

FIG. ll is an axial detail view on an enlarged scale of the spider oradapter which I may employ to center an annular rotary brush elementwithin the mold during the centrifuging operation.

The brush type rotary tool or wheel illustrated in FIGS. 1 and 2 of thedrawing is illustrative of the various products of this invention. Insuch illustrative embodiment, the tool or wheel comprises an annularrotary brush section which may, for example, be of the type disclosed inWhittle Patent 2,288,337 having an annular channel back 1 in whichradially outwardly extending bristles 2 are secured, and an annular body3 of plastic intruded between and embedding such bristles. The plasticmay preferably but not necessarily be a resiliently dcformable cellularcomposition and foamed polyurethane is a preferred material for thepurpose.

One or more of such annular brush sections may be assembled in axiallyaligned relationship within an appropriate mold (FIG. 3), or, forexample, helically wound brush strip such as that shown in PetersonPatent 2,363,386 may similarly be employed. Such mold may desirablycomprise an annular outer ring 4 adapted to be centered and clampedbttween lower and upper face plates 5 and 6 respectively, the assemblybeing thus clamped together by means of nut 7 on central threaded stud8.

The annular brush section may be centered within the mold thus formed bymeans of a spider 9 which may be sheet metal stamping of the formillustrated in FIG. 11 having a central opening 10 and a plurality ofradially outwardly extending legs such as 11 terminating in axiallyofiset portions such as 12 which serve to engage the inner periphery ofthe annular channel back 1, opening 10 fitting over central stud 8. Theover-all diameter of the brush section will preferably be somewhat lessthan the inner diameter of mold ring 4 so as to provide an annular spacebetween the ends of the bristles and the mold. When a foamable plasticmaterial is to be used to fill the brush, the stud 8 will also desirablybe provided with a central vent passage 13 therethrough communicatingwith the interior of the mold.

In a typical operation, a foamable fiowable plastic material may bedischarged in predetermined quantity from container 14 into the openmold wherein the annular brush section has been centered, such moldbeing mounted on a turntable or centrifuge 15 for rotation about thevertical axis of stud 8. After such measured charge 16 has been thusdeposited in the mold generally centrally thereof as shown in FIG. 4,the cover plate 6 is placed in position and secured by means of nut 7.The mold may thereupon be rotated at sufficiently high speed to produceeffective centrifuging action, e.g. at 3,000 r.p.rn. for 45 seconds whenemploying the preferred polyurethane composition to cause the plasticcharge 16 to flow radially outwardly of the end faces of the annularbrush section to the annular space between the brush bristle ends andthe inner peripheral surface of mold ring 4, the plastic materialthereupon flowing radially inwardly between the bristles until acondition of substantially dynamic balance is achieved as shown in FIG.6. As the polyurethane constituents continue to react, the plasticcharge 16 gradually becomes less liquid and more viscous and at thisstage rotation of the mold will be stopped or very substantially reducedto encourage foaming of the plastic charge in this condition as shown inFIG. 7. Such foaming action, of course, serves to expand such plasticcharge radially inwardly of the mold with further intrusion of theplastic material between the brush bristles, the direction of suchexpansion being such that the proper uniform spacing of the bristlesremains substantially unaffected thereby. Air and other gases may escapefrom the mold through the aforesaid vent passage 13 in central stud 8.The charge may be of such precisely predetermined volume that it willfill the mold only to the extent illustrated in FIG. 8 and after propercuring, the finished article may be removed therefrom and separated fromthe spider or adapter 9. More generally, the foaming plastic materialwill be employed in such quantity as to fill the mold completely asshown in FIG. 9. When the molded article is then removed, it may bemounted upon an arbor or mandrel of the same diameter as stud 8 for use,or the center portion including the spider 9 may be punched out and theresultant article (as shown in FIG. 1, for example) mounted upon anappropriate arbor or adapter of the same diameter as that of the innerperiphery of the annular channel brush back 1.

Now referring more specifically to FIGS. 1 and 2 of the drawing, theembodiment of the invention there illustrated also includes annular ribs17 and 18 of plastic material integral with the plastic material withwhich the brush is filled, such ribs being molded on the respective endfaces of the tool and spaced inwardly from the working face of such toola substantial distance which may be on the order of about one-third ofthe radial extent of the annular body of the tool. Such ribs strengthenthe wheel and assist in limiting deep radial tearing of the cellularplastic or resin between the bristles in use. Such ribs are, however,ordinarily not essential. In view of the fact that the outer ends of thebrush bristles 2 were spaced inwardly from the inner peripheral surfaceof the mold, there will be an outer circumferential layer of foamedplastic material on the working face of the tool. Such layer will,however, promptly be eliminated upon placing the tool in operation ormay desirably previously be removed by engagement with an appropriatepower driven rotary wire brush.

When a non-foaming resin is employed to fill the brush, a larger chargewill, of course, ordinarily be deposited in the mold which may berotated to facilitate filling of the mold. The cover plate 6 may then beapplied and the mold rotated at high speed to cause the plastic materialto flow radially outwardly across the respective end faces of the brushelement to the annular space between the bristle ends and the innerperipheral surface of ring 4 and then radially inwardly between suchbristles until a condition of dynamic equilibrium is reached. Theplastic material will ordinarily be caused at least partially to gel, asby application of heat, before removal of the composite tool from themold, although when employing some relatively viscous fluid fillermaterials which adhere tenaciously to the brush bristles and do not tendto drain rapidly from the latter, the treated brush section maysometimes be promptly removed from the mold for drying, curing orsetting.

When the brush material is highly flexible or even limp in character, asin the case of certain types of cord, fine wire, glass fiber and thelike, it will ordinarily be important at least partially to set theplastic material prior to cessation of the centrifuging operation, thisfor the reason that the centrifugal action is relied upon to hold suchbrush material in proper radially extended condition during intrusionand setting of the filler material. Even when using rather stifferbristle material such as a mixture of steel wire and tampico fiber, forexample, such centrifugal action is highly advantageous in maintainingproper desired orientation of the bristles during intrusion of theplastic material and until the latter has at least partially set. Aswill thus be seen, the centrifugal action brings the bristles intorotary dynamically oriented relationship in substantially true radialpositions, and the plastic material intruded between the bristlesmaintains them spaced apart in such dynamically oriented positions.

As may be deduced from the foregoing, a wide variety of brush materialmay be utilized in accordance with the present invention, depending uponthe characteristics of the resultant brushing tool desired. Thus,relatively hard brittle steel wire bristles having a Knoop hardness inexcess of 600 and even in excess of 800 may desirably be employed toproduce a composite tool having rapid cutting action on the work, afoamed e-lastomeric polyurethane composition being intruded between suchbristles to damp vibration and support the same. The brush material may,on the other hand, comprise vegetable fiber such as tampico fiber andsisal, glass fiber which may be either in the form of relatively stiffhard monofilaments or relatively soft fine stranded cords, plasticfilaments such as nylon monofilaments, copper wire, stainless steel wireand the like. The brushing material may also be in the form of a porousfibrous batt comprising a mass of filamentous or fibrous material suchas chopped tampico fiber bonded together by a suitable adhesive, thefoamed plastic filler material being intruded therein in the same mannerdescribed above in the case of a more conventional rotary brush section.

Suitable granular abrasives such as aluminum oxide, silicon carbide,pumice and rouge may be incorporated in the plastic filler material andthereby intruded into the brush for application to the work as the brushface wears back in use. Such granular abrasive thus incorporated in acellular plastic structure is made available at the working face of thetool when needed, but in the meantime is held in a manner which preventsdestructive action of the abrasive upon the brush filaments themselves.

As well shown in FIG. 2, the method of manufacture above described alsousually results in the formation of a thin plastic skin on the axial endfaces of the resultant composite tool which considerably reinforces thelatter. Even when a foaming plastic composition is employed, such skinwill ordinarily be relatively smooth and impervious. It is generallypreferred that the cells formed by the foaming operation not be incommunication with one another, but rather that the product be of theclosed cell type as there will then be little or no tendency of the toolto absorb liquids under conditions of use which might deleteriouslyaflfect the structure and cause undesirable imbalance of the wheel whenrotated at high operating speeds. While rotary brush sections havingannular metal backs may frequently constitute a preferred component ofthe new composite tool, it is not essential that such annular back-s beemployed and the brush material may simply be doubled about an annularring in wellknown manner, or no retaining element at all may be utilizedas in the case of the porous batt of fibrous material mentioned above.Similarly, the brush bristle material may simply be distributed radiallywithin the mold with the inner ends thereof being bonded together bymeans of a suitable adhesive or by interfusion of such ends as whenplastic bristles such as nylon are employed. Particularly good resultsare obtained when practicing the method of this invention and utilizingbeaded bristle material of the type disclosed and claimed in mycopending application Serial No. 86,378, filed February 1, 1961, forBrush and Brush Material, now Patent No. 3,090,061.

While the hereinafter described polyurethanes are ordinarily preferredfor my purpose, certain other plastic compositions or resins may beutilized in achieving some of the benefits of my invention; for example,phenolic, epoxy, natural rubber, polyisoprene, butadiene-styrene,butadieneacrylonitriile, and polyvinyl chloride resins, especiallyfoams. Abrading wheels of epoxy resin foam and abrasive, and wheels ofvinyl plastisol and abrasive are especially useful for some purposes.

Among presently available compositions, I prefer to employ as theelastomeric material to form the body one of the isocyanate resins,known as polyurethanes, which are formed by the reaction of thediisocyanate (usually toluene diisocyanate) with a polyester and/orpolyether, the result of the reaction being the formation of a longchain polyurethane. The addition of water (and/ or acid) to the reactionmixture causes cross-linking of the polyurethane chains, releasingcarbon dioxide which serves as a foaming agent.

The reagents, and in particular the polyester, employed in making thefoamed polyurethane elastomeric body will vary depending upon the degreeof resiliency or rigidity and other characteristics which it is desiredsuch body should possess. For the polyester, one of the series currentlymarketed by American Latex Products Corporation, of Hawthorne,California, under the trade name Stafoam has been found satisfactory.One of the 300 Series products under this trade name, more specificallyone of such series containing at least one or more benzene rings, willproduce a relatively rigid body. The following is another formulationusing a resin sold by Nopco Chemical Company under the trade nameLockfoam which will produce a resilient wheel:

189 grams A-516-R Lockfoam resin manufactured by The Nopco ChemicalCompany 11 grams A-S 1 6C foaming agent also manufactured by The NopcoChemical Company Another formulation including a polyester selectedaccording to the degree of resilience desired is as follows:

Parts by weight Polyester 100.0 Toluene diisocyanate 35.0 Water 2.4N-methylmorpholine 1.3 Glycerol monoricinoleate 1.0

The urethane polymers have been found to provide a high degree ofadhesion to abrasive grains and the like, permitting dense concentrationof such abrasive grains in the working portion of the abrading tool, theamount of polyurethane in the interstices between such grains andserving to bond the same together being further reduced by the inherentfoaming reaction (due to presence of water) or by inclusion of aconventional blowing compound which serves to produce a multitude ofsmall cells Within such interstices. The centrifugal action employed inthe production of the composite tool also assists in concentrating theabrasive grains in the outer peripheral portion of such tool where theymay be effectively utilized.

While the articles with which the present invention is concerned willgenerally include a yielding resiliently deformable body, which may beof polyurethane rubber for example, such body will ordinarily preferablybe of resiliently deformable cellular composition such as foamedpolyurethane to afford the desired degree of support and control for theradially extending brush bristles. Where a substantial degree of truebrushing action is not required or desired, however, as in the case ofcertain abrading tools having a high concentration of granular abrasivein the outer peripheral portions thereof, a relatively rigid plasticbody comprising, for example, one of the more rigid polyurethanecompositions may instead be employed, but such relatively rigid bodywill also normally desirably he of cellular structure. Tools of theseseveral types are adapted to a variety of different uses includingsurface finishing, burr removal and the like. They may also be employedin certain quite unrelated fields as, for example, wheels for supportingor propelling various vehicles.

Other modes of applying the principle of the invention may be employed,change being made as regards the details described, provided thefeatures stated in any of the following claims or the equivalent of suchbe employed.

I therefore particularly point out and distinctly claim as my invention:

1. A brush type rotary tool comprising a rotatable central support and alarge number of elongated brushing elements extending substantiallydirectly radially outwardly therefrom with a body of plastic interposedbetween said elements and maintaining the same substantially uniformlyspaced apart to ensure uniform brushing element tip spacing at theWorking face of the tool, said plastic body including an integralannular rib on each respective end face of said tool spaced inwardlyfrom the working face of the tool to strengthen the latter.

2. A new rotary brush-like product comprising a central support withbristles secured thereto and extending generally radially outwardlytherefrom, said bristles being in rotary dynamically orientedrelationship in substantially true radial positions with substantiallyuniform spacing therebetween, and a body of plastic material betweensaid bristles maintaining said bristles spaced apart in theirdynamically oriented positions.

3. The product of claim 2, wherein said bristles comprise fine filamentswhich are normally somewhat limp.

4. The product of claim 2, wherein said bristle-s are flexible and thusspaced apart and supported by a resiliently deformable cellular plasticcomposition.

5. The product of claim 2, wherein said bristles are thus spaced apartand supported by a polyurethane plastic.

6. The product of claim 2, wherein said bristles are thus spaced apartand supported by a foamed polyurethane plastic.

References Cited by the Examiner UNITED STATES PATENTS 1,038,682 9/1912Thompson 2265 2,648,084 8/1953' Swart 15-198 2,680,335 6/1954 Hurst51504 2,785,442 3/1957 Boggs 264- 311 X 2,862,806 12/1958 Nestor 264-311 X 2,950,495 8/ 1960 Stingley 15-179 2,972,527 2/1961 Upton 51296 X2,995,401 8/ 1961 Peterson 300-21 3,076,219 2/1963 Peterson 15-179FOREIGN PATENTS 1,006,829 4/1957 Germany.

CHARLES A. WI-LLM-UTH, Primary Examiner.

PETER FEDDMAN, Assistant Examiner.

2. A NEW ROTARY BRUSH-LIKE PRODUCT COMPRISING A CENTRAL SUPPORT WITHBRISTLE SECURED THERETO AND EXTENDING GENERALLY RADIALLY OUTWARDLYTHEREFROM, SAID BRISTLES BEING IN ROTARY DYNAMICALLY ORIENTEDRELATIONSHIP INSUBSTANTIALLY TRUE RADIAL POSITIONS WITH SUBSTANTIALLYUNIFORM SPACING THEREBETWEEN, AND A BODY OF PLASTIC MATERIAL BETWEENSAID BRISTLES MAINTAINING SAID BRISTLES SPACED APART IN THEIRDYNAMICALLY ORIENTED POSITIONS.